242 TI * E GEOLOGY OF MINNESOTA. 



[Elevations. 



tributary valleys which are themselves nearly as deep, and penetrate often 

 many miles westward into the rocky structure of the land ; where they are 

 found to terminate in precipitous rocky gorges, perhaps with small rivulets 

 plunging over the cliffs, or in the mouths of copious subterranean streams. 

 These tributaries have sub-tributaries, branching from them in all directions, 

 each one reproducing, but with thousand-fold diversities, the features of its 

 main, embracing the whole country in a network of vales and bluffs. Thus 

 the beholder is constantly enlivened by a shifting panorama, as he travels 

 from "the great river" westward. When he rises finally upon the elevated 

 prairie plateau in the central part of the county, if with an inquiring glance 

 he retroverts toward the east, the relation of cause and effect, which under 

 natural laws has wrought out the valleys, the headlands, the terraces, the 

 narrow gorges, is so evident to his mind that his appreciative sense of the 

 beautiful in the landscape is intensified and also deepened. The valley of 

 the Whitewater river, which is remarkable for its great depth combined 

 with its narrowness, affords many fine landscape scenes in the town of Elba. 



Elevations. Numerous observations were made by aneroid barometer 

 for the elevation of bluffs and terraces throughout the county, and on these 

 observations, reduced to the ocean level by connection with railroad sta- 

 tions, the contour-lines of the county map were established. In passing 

 over the country, between railroad stations, and in all lines remote from 

 railroads, the topography was outlined by the eye, estimates being made on 

 the variations from known contours. 



The bluffs at Beaver were ascertained in this manner to rise 480 feet 

 above the alluvial flat on which the village is situated. The flat is so near 

 the Whitewater level that it is sometimes flooded, being about eight feet 

 above the river at low water. This hight is reached about a quarter of a 

 mile back from the brow of the St. Lawrence limestone, but does not include 

 the Shakopee limestone. The 950 feet contour-line just about coincides 

 with the top of the St. Croix sandstone at Beaver. 



Where the road crosses the south branch of the Whitewater, between 

 sections 2 and 3, St. Charles, the creek is about 1030 feet above the ocean, 

 and the cut in the St. Lawrence is about fifty feet. 



Lewiston, at 1211 feet, is about the average hight of the prairie about 

 there. It includes the Jordan and Shakopee formations. 



